Lua installation guide

Here is a super simple step-by-step instruction to install the latest versions of lua + luajit + luarocks on linux and use them together without conflicts.

The main differences between this method and more complex scripts that allow you to manage versions:

📋 Spoiler

• First at all this is not a lua version manager. Instead of switching between lua and luarocks, they are used simultaneously: lua ... or luajit ... to run and luarocks --lua-version=5.4 ... or luarocks ... to install packages. Installing multiple versions the same way is possible, but not recommended.
• So, the main priority is stability (conflict-free). Complex scripts most often installing different versions of lua but do not care about how they integrate with luarocks. This causes luarocks to install the wrong packages versions and leads to unpredictable errors.
• In order to achieve my goal, I had to adhere to the most standard standards! The libraries by default will be installed and searched only in /usr/local/lib/lua/ or /usr/local/share/lua/. The installation is almost exactly the same as the recommended instructions on the official sites and my scripts doesn't touch the source files at all. Sudo is required, because the untouched lua installed locally doesn't know where to search local libraries.
• Luarocks itself works on luajit.

1. Install dependencies

This instruction is for Ubuntu but it should not be much different for other distributions:

sudo apt install build-essential libreadline-dev unzip libssl-dev

Optionally (read below):

sudo apt install rlwrap

2. Download and unpack

• lua
• luajit
• luarocks

3. Build and install

0. Update versions in the scripts to yours.
1. install-lua.sh
2. install-luajit.sh
3. install-luarocks.sh
4. install-core-packages.sh

4. Check installation

Run commands: luarocks and luarocks --lua-version=5.4. You should see something like this:

📋 Spoiler

Configuration:
   Lua:
      Version    : 5.1
      Interpreter: /usr/local/bin/luajit (ok)
      LUA_DIR    : /usr/local (ok)
      LUA_BINDIR : /usr/local/bin (ok)
      LUA_INCDIR : /usr/local/include/luajit-2.1 (ok)
      LUA_LIBDIR : /usr/local/lib (ok)

   Configuration files:
      System  : /usr/local/etc/luarocks/config-5.1.lua (ok)
      User    : disabled in this LuaRocks installation.

Configuration:
   Lua:
      Version    : 5.4
      Interpreter: /usr/local/bin/lua (ok)
      LUA_DIR    : /usr/local (ok)
      LUA_BINDIR : /usr/local/bin (ok)
      LUA_INCDIR : /usr/local/include (ok)
      LUA_LIBDIR : /usr/local/lib (ok)

   Configuration files:
      System  : /usr/local/etc/luarocks/config-5.4.lua (ok)
      User    : disabled in this LuaRocks installation.

If everything is (ok) then ok. 👌

5. Solve problems

There is a known issue: when you run lua or luajit in terminal and try to use arrow keys, you will most likely see some gibberish, like this: ^[[D^[[C.

To solve this problem run wrap.sh. If this problem doesn't bother you, though, I don't recommend using this hack.

Another minor problem is that luajit's default paths are a bit retarded and if you have an "init.lua" file in the directory "folder", you cannot require "folder" from luajit, although everything works fine in lua.

Of course, you could tweak the configuration files and fix everything, but just because you fix it doesn't mean that all other users will do the same. So the best solution I see here is to add the package.path = "?/init.lua;" .. package.path to your scripts.